Optical flow cells are used within a plurality of technical fields where a solution is allowed to flow across a detector that serves to determine a concentration of a substance within the solution. Examples of such technical fields are fluid chromatography and filtering, among others.
The detectors used in the flow cells are generally optical detectors, having a first light guide with an exit surface where light is emitted and a second light guide with an entrance surface where the light is received. The distance between the exit surface and entrance surface can be relatively long for solutions of lower concentration, but in order to achieve reliable detection also for solutions of high concentration the distance should be smaller, typically in the range of 0.1-0.2 mm. To achieve satisfactory quality of measurements, the distance must be kept constant and is not allowed to deviate from a set value more than 5%.
To enable precision when manufacturing and mounting detectors, the light guides used should be held by light guide holders that can be fastened in a detector or a flow cell directly. However, to manufacture such a light guide holder with high precision is difficult, and care must be taken during insertion to prevent damages such as scratches or distortions to the shape of the light guide. This would otherwise result in a significantly lowered performance of the light guide and the measurements performed in the flow cell. Thus, it is a common problem to ascertain that no damage has been done to a light guide during mounting and that the light exit surface or light entrance surface that is to be used for measurements has not been scratched or otherwise damaged. There is a constant need for improvements within this area and for light guide holders that can overcome these drawbacks.